Abstract

We investigate the radiative B-c -> D-s1 gamma transition in the framework of QCD sum rules. In particular, we calculate the transition form factors responsible for this decay in both weak annihilation and electromagnetic penguin channels using the quark condensate, mixed, and two-gluon condensate diagrams, as well as propagation of the soft quark in the electromagnetic field, as nonperturbative corrections. These form factors are then used to estimate the branching ratios of the channels under consideration. The total branching ratio of the B-c -> D-s1 gamma transition is obtained to be of the order of 10(-5), and the dominant contribution comes from the weak annihilation channel.